The sousaphone I'm speaking of in another question has "J 41" embossed near the screws that hold the bell. I'm wondering if this could be a model name. Does anyone know the brand ? Or the place where ...

I've recently bought a cheap battered second (probably mode) hand sousaphone on a garage sale. It is in faily bad shape, but the valves look ok.
The instrument is made of a metallic grey alloy which ...